Private gold pieces, sometimes dubbed "pioneer gold", were several times during the 19th century struck from locally produced bullion in areas where federal coins were scarce. These unofficial coins came from sites ranging from Georgia to Oregon. Many, ranging in denomination from 25 cents to 50 dollars, are relics of the California Gold Rush and its aftermath. The fifty-dollar denomination was struck by private minters such as Kellogg and Co. The private $50 pieces were round in form, but those struck by Augustus Humbert for the U.S. Assay Office at San Francisco, prior to the establishment of the San Francisco Mint in 1854, were octagonal. Humbert''''s pieces were not money in a legal sense, as Congress had not authorized them as legal tender, and were officially deemed ingots. Nevertheless, they contained their full value in gold. Bearing the denomination "Fifty Dollars", they were called "slugs" or "quintuple eagles" by the public. They circulated widely in California and elsewhere in the Far West, and were accepted on par with federal gold coins.[1] All of these $50 pieces, public or private, are very rare and valuable today: One of Humbert''''s octagonal pieces, dated 1851 and with a lettered edge, sold at auction in 2010 for $546,250.[1] The only $50 piece produced by the United States Bureau of the Mint prior to 1915 was the 1877 pattern half union, produced experimentally at the Philadelphia Mint, though it was not approved as a circulating coin.[2] In 1904, San Francisco merchant Rueben Hale proposed an exposition in his home city for 1915, both to commemorate the opening of the Panama Canal and to mark the 400th anniversary of Vasco Núñez de Balboa becoming the first European known to view the Pacific Ocean from the Americas: in phrasing then current, he discovered the Pacific. Although the 1906 San Francisco earthquake and fire caused a momentary setback to these plans, it actually sparked additional fundraising. Many of the wealthiest in California gave financial support, the state matched private donations dollar for dollar, and in 1911, President William Howard Taft selected San Francisco over its competitor, New Orleans, to host the fair.[3] Numismatist Farran Zerbe The Panama–Pacific International Exposition, constructed in San Francisco by the Golden Gate at a cost of $50 million, was open from February 20, 1915, to December 4, 1915.[4] About 19,000,000 people attended, and the exposition was a great success,[5] generating enough profit to build the San Francisco Civic Auditorium with about $1 million remaining.[6] The Palace of Fine Arts is the only building from the fair which remains on the site.[7] Commemorative coins were not then sold to the public by the Mint, as they subsequently have been. Instead, a commemorative''''s authorizing legislation would designate a group or organization to purchase the coins from the Mint at face value, and sell them to the public as a fundraiser.[8] Among those who had pushed for commemorative legislation in the past, and had been involved in the sale of the resulting coins, was Farran Zerbe, a collector and numismatic promoter who had by 1914 served as president of the American Numismatic Association. Zerbe was a controversial figure—some felt the coins with which he had been involved had been sold at inflated prices—but he helped promote the hobby with his exhibit, "Money of the World", which later became part of the Chase Manhattan Money Museum.[9][10] Legislation[edit] Aerial view of the Panama–Pacific International Exposition Several proposals for commemorative coins had been introduced by mid-1914, though none had been issued by the Mint since 1905. One, sponsored by New York Senator Elihu Root, called for a commemorative quarter dollar marking a century of peace, as well as the August 1914 opening of the Panama Canal.[11] Two bills were introduced calling for coins to commemorate and benefit the Panama–Pacific Exposition; H.R. 16902 was introduced by California Congressman Julius Kahn on June 3, 1914.[12] Senate bill (S.) 6309 was introduced in that body by New Jersey Senator James E. Martine on July 6. This bill called for two $50 pieces (one round, one octagonal), a quarter eagle or $2.50 in gold, a commemorative gold dollar, and a half dollar.[13] The octagonal pieces were intended to recall the unofficial $50 coins struck during the Gold Rush[14] Martine''''s bill passed the Senate on August 3, having been approved by the Committee on Industrial Expositions, to which it had been referred. The only objection was procedural, by Utah''''s Reed Smoot: that the bill should have instead been referred to and approved by the Senate Committee on Banking and Currency, or its Committee on Finance. Neither Smoot nor any other senator objected to the bill itself, which Martine indicated had the support of Treasury Secretary William G. McAdoo.[15] S. 6309 was the following day sent to the House of Representatives, where it was referred to the Committee on Coinage, Weights and Measures. It emerged from that committee on September 1, 1914, with several amendments, one of which increased the combined authorized mintage of the two $50 pieces from 2,000 to 3,000.[16] S. 6309 was briefly considered by the House of Representatives on January 4, 1915, and passed after Kahn successfully proposed a minor amendment to strike out the dollar sign from the phrase "silver coins of the denomination of $50 cents each".[16][17] The Senate concurred in the House amendments two days later, passing the bill without question, change, or opposition,[18] and President Woodrow Wilson signed it into law on January 16